SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

RULE 4661 - ORGANIC SOLVENTS 

(Adopted May 21, 1992)(Amended December 17, 1992; December 9, 1999; December 20, 2001; 

May 16, 2002; September 20, 2007). 

1.0 Purpose 

 The purpose of this rule is to limit the emissions of volatile organic compounds (VOCs) 

from the use of organic solvents. This rule also specifies the reduction, monitoring, 

reporting, and disposal requirements. 

2.0 Applicability 

 The provisions of this rule shall apply to any source operation that uses organic solvents 

unless the source operation is exempted under Section 4.0. 

3.0 Definitions 

3.1 APCO: as defined in Rule 1020 (Definitions). 

3.2 ARB: California Air Resources Board. 

3.3 Baked: a process whereby the coated object is heated above ambient temperature 

to a temperature at or above 194°F for the purpose of curing or drying. 

3.4 Dissolver: an organic solvent that is added to an adhesive, coating, or ink in order 

to melt or to liquefy solid particles. 

3.5 EPA: United States Environmental Protection Agency. 

3.6 Exempt Compounds: all organic compounds not classified as VOC, as listed in 

the definition of VOC in Rule 1020 (Definitions). 

3.7 Grams of VOC per liter of Material: the weight of VOC per volume of material 

and is calculated by the following equation: 

Grams of VOC per liter of material = Ws – Ww – Wec

Vm 

Where: 

Ws = Weight of volatile compounds, in grams 

Ww = Weight of water, in grams 

Wec = Weight of exempt compounds, in grams 

Vm = Volume of material, in liters. 

3.8 Heat-Cured or Heat-Polymerized: heated to a temperature less than or equal to 

194o

F for the purpose of curing a coating, ink or adhesive. 

3.9 Normal Business Hours: Monday through Friday, 8:00 am to 5:00 pm. 

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3.10 Organic Solvent: the same as “Solvent.” 

3.11 Organic Solvent Cleaning: as defined in Rule 4663 (Organic Solvent Cleaning, 

Storage, and Disposal). 

3.12 Photochemically Reactive Solvent: any organic solvent with an aggregate of 

more than 20% of its total volume composed of chemical compounds classified 

below or which exceeds any of the following individual percentage composition 

limitations referring to the total volume of solvent: 

3.12.1 A combination of hydrocarbons, alcohols, aldehydes, esters, ethers or 

ketones having an olefinic or cycloolefinic type of unsaturation: five (5) 

percent; or 

3.12.2 A combination of aromatic compounds with eight (8) or more carbon 

atoms to the molecule except ethylbenzene: eight (8) percent; or 

3.12.3 A combination of ethylbenzene, ketones having branched hydrocarbon 

structures, or toluene: 20%. 

Whenever any organic solvent or any constituent of an organic solvent may be 

classified from its chemical structure into more than one (1) of the above groups 

of organic compounds, it shall be considered as a member of the most reactive 

chemical group, that is, that group having the least allowable percentage of the 

total volume of solvents. 

3.13 SCAQMD: South Coast Air Quality Management District. 

3.14 Solvent: as defined in Rule 4663 (Organic Solvent Cleaning, Storage, and 

Disposal). 

3.15 Standard Conditions: as defined in Rule 1020 (Definitions). 

3.16 Thinner or Viscosity Reducer: an organic solvent which is used to dilute coatings 

to reduce viscosity, color strength, and solids, or to modify drying conditions. 

3.17 Volatile Organic Compound (VOC): as defined in Rule 1020 (Definitions). 

4.0 Exemptions 

The provisions of this rule shall not apply to: 

4.1 The manufacture of organic solvents, or the transport of organic solvents or 

materials containing organic solvents. 

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4.2 Any source operation that is subject to or specifically exempted by any of the 

following rules: 

4.2.1 Rule 4601 (Architectural Coatings), 

4.2.2 Until December 31, 2008, Rule 4602 (Motor Vehicle and Mobile 

Equipment Coating Operations), 

4.2.3 Rule 4603 (Surface Coating of Metal Parts and Products), 

4.2.4 Rule 4604 (Can and Coil Coating Operations), 

4.2.5 Rule 4605 (Aerospace Assembly and Component Coating Operations), 

4.2.6 Rule 4606 (Wood Products Coating Operations), 

4.2.7 Rule 4607 (Graphic Arts), 

4.2.8 Rule 4610 (Glass Coating Operations), 

4.2.9 On and after January 1, 2009, Rule 4612 (Motor Vehicle and Mobile 

Equipment Coating Operations – Phase II), 

4.2.10 Rule 4653 (Adhesives), 

4.2.11 Rule 4662 (Organic Solvent Degreasing Operations), 

4.2.12 Rule 4684 (Polyester Resin Operations), or 

4.2.13 Rule 4691 (Vegetable Oil Processing Operations). 

4.3 The spraying or other employment of insecticides, pesticides or herbicides. 

4.4 The employment, application, evaporation, or drying of saturated halogenated 

hydrocarbons or perchloroethylene. 

4.5 The use of any material, in any source operation described in Sections 5.1, 5.2, 

5.3, or 5.4 if all of the following conditions are met: 

4.5.1 The volatile content of material consists only of water and organic 

solvents, and 

4.5.2 The organic solvents content comprises not more than 20 percent by 

volume of the total volatile content, and 

4.5.3 The volatile content is not photochemically reactive, and 

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SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

4.5.4 The organic solvent does not come into contact with flame. 

5.0 Requirements 

5.1 Sections 5.2 through 5.7 shall remain in effect until March 20, 2008. 

5.2 Solvents Subjected to Heat: An operator shall not discharge into the atmosphere 

more than 15 pounds of VOC emissions in any one (1) day from any source 

operation in which any organic solvent or any material containing organic 

solvents comes into contact with a flame or is baked, heat-cured, or heatpolymerized in the presence of oxygen, unless the VOC emissions have been 

reduced through the operation of an APCO-approved VOC emissions control 

system with an overall capture and control efficiency of at least 85 percent by 

weight. Those portions of any series of source operation designed for processing 

continuous web, strip, or wire that emit VOCs in the course of using operations 

described in this section shall be collectively subject to compliance with this 

section. 

5.3 Photochemically Reactive Solvents: An operator shall not discharge into the 

atmosphere more than 40 pounds of VOC emissions in any one (1) day from any 

source operation resulting from conditions other than those described in Section 

5.1 for employing or applying any photochemically reactive solvent, or any 

material containing such photochemically reactive solvent, unless the VOC 

emissions have been reduced through the operation of an APCO-approved VOC 

emissions control system with an overall capture and control efficiency of at least 

85 percent by weight. Emissions resulting from baking, heat-curing, or heatpolymerizing, as described in Section 5.2 of this rule, shall be excluded from 

determination of compliance with this section. Those portions of any series of 

source operation designed for processing a continuous web, strip, or wire that 

emit VOCs in the course of using operations described in this section shall be 

collectively subject to compliance with this section. 

5.4 Non-photochemically Reactive Solvents: An operator shall not discharge into the 

atmosphere more than 3,000 pounds of VOC emissions in any one (1) day from 

any source operation in which any non-photochemically reactive organic solvent 

or any material containing such a solvent, is employed or applied, unless VOC 

emissions have been reduced through the operation of an APCO-approved VOC 

emissions control system with an overall capture and control efficiency of at least 

85 percent by weight. Emissions resulting from baking, heat-curing, or heatpolymerizing, as described in Section 5.2 of this rule, shall be excluded from 

determination of compliance with this section. Those portions of any series of 

source operation designed for processing a continuous web, strip, or wire that 

emit VOCs in the course of using operations described in this section shall be 

collectively subject to compliance with this section. 

5.5 Cleanup: Emissions of VOCs into the atmosphere resulting from cleanup 

operations utilizing photochemically reactive organic solvents, from any source 

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operation described in Sections 5.2, 5.3, or 5.4 shall be included with other 

emissions of VOCs from that source operation for determining compliance with 

this rule. 

5.6 Post Removal Drying: Emissions of VOCs into the atmosphere as a result of 

spontaneously continuing drying of products for the first 12 hours after their 

removal from any source operation described in Sections 5.2, 5.3, or 5.4 shall be 

included with other emissions of VOCs from that source operation for 

determining compliance with this rule. 

5.7 Monitoring: An operator incinerating, adsorbing, or otherwise processing organic 

solvents pursuant to this rule shall provide, properly install and maintain in 

calibration, in good working order and in operation, devices as specified in the 

Authority to Construct or the Permit to Operate, or as specified by the APCO, for 

indicating temperatures, pressures, rates of flow or other operating conditions 

necessary to determine the degree and effectiveness of the VOC emission control 

system. 

5.8 On and after March 21, 2008, from all VOC-containing materials, equipment, and 

processes subject to this rule, an operator shall not emit to the atmosphere VOCs 

in excess of 833 pounds VOC per calendar month per facility. 

5.9 In lieu of meeting the VOC emission limit in Section 5.8, an operator may install 

and operate a VOC emission control system that meets the following 

requirements. 

5.9.1 The VOC emission control system shall be approved by the APCO. 

5.9.2 The VOC emission control system shall have a capture efficiency of at 

least 90 percent by weight (90 wt%) and a control efficiency of at least 95 

wt%. 

5.10 Organic Solvent Cleaning, Storage, and Disposal Requirements 

Operators shall comply with the requirements of Rule 4663 (Organic Solvent 

Cleaning, Storage, and Disposal) when performing organic solvent cleaning, 

storage and disposal of organic solvents and waste solvent materials, coatings, 

adhesives, catalysts, and thinners. See Sections 5.0 and 6.0 of Rule 4663 for 

solvent VOC content limits, work practices, recordkeeping, and testing 

requirements. 

6.0 Administrative Requirements 

6.1 Recordkeeping 

6.1.1 Until March 20, 2008, the records shall identify the organic solvents used in 

all source operations and shall include the name of each organic solvent, 

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SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

solvent manufacturer’s name, chemical composition, VOC content, vapor 

pressure, amount used. 

6.1.1.1 An operator of a coating operation subject to this rule shall 

maintain daily records. 

6.1.1.2 For other operations subject to this rule, records may be kept on an 

extended basis, but not to exceed monthly, and shall not exceed a 

period during which the amount of VOC emissions exceeds the 

applicable daily VOC emission limits in the rule. 

6.1.1.3 Solvent purchase records and other such records needed to verify 

compliance of emissions limits of the rule shall also be kept. 

6.1.1.4 Other such records, including the amount of VOC emissions 

resulting from organic solvent cleaning operations subject to Rule 

4663 utilizing photochemically reactive organic solvents, needed to 

verify compliance of emissions limits of the rule shall also be kept. 

6.1.2 On and after March 21, 2008, operators shall 

6.1.2.1 Materials List: An operator shall maintain and have available on 

site, a current list of materials in use which provides all of the data 

necessary to evaluate compliance including the following 

information as applicable: 

6.1.2.1.1 Specific manufacturer’s name of solvent-containing 

material, including solvents, catalysts, and thinners. 

6.1.2.1.2 VOC content of each solvent-containing material, as 

used, in g/l or lb/gal. 

6.1.2.2 Material Usage Records – An operator shall maintain usage 

records on a daily basis that include the following information: 

6.1.2.2.1 Specific material. 

6.1.2.2.2 Volume of material used (gallons). 

6.1.2.2.3 Specific solvents, catalysts and thinners added to 

material. 

6.1.2.2.4 Volume of each solvent, catalyst and thinner (gallons) 

added. 

6.1.2.2.5 When the material is a mixture of different materials 

that are blended by the operator, the mix ratio of the 

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batch shall be recorded and the VOC content of the 

batch shall be calculated and recorded in order to 

determine compliance with the VOC emission limits. 

6.1.3 VOC Emission Control System Records 

An operator using a VOC emission control system as a means of 

complying with this rule shall maintain daily records of key system 

operating parameters which will demonstrate continuous operation and 

compliance of the VOC emission control system during periods of 

emission-producing activities. 

6.1.4 Records Retention 

An operator shall retain records required in Sections 6.1.1 through 6.1.3, 

as applicable, on site for a minimum of five (5) years, make the records 

available on site during normal business hours to the APCO, ARB, or EPA 

and submit the records to the APCO, ARB, or EPA upon request. 

6.2 Test Methods 

6.2.1 Determination of VOC Content 

6.2.1.1 The VOC content of organic solvents shall be determined by 

using EPA Test Method 24 or 24A or by using the 

manufacturer’s product formulation data and the formula in 

Section 3.7. 

6.2.1.2 Exempt halogenated VOCs shall be determined by using the 

ARB Test Method 432 or SCAQMD Test Method 303. 

6.2.2 Determination of Overall Capture and Control Efficiency of VOC 

Emission Control Devices 

6.2.2.1 The capture efficiency of a VOC emission control system’s 

collection device(s) shall be determined according to EPA’s 

“Guidelines for Determining Capture Efficiency,” January 9, 

1995 and 40 CFR 51, Appendix M, Test Methods 204-204F, as 

applicable, or any other method approved by EPA, ARB, and the 

APCO. 

6.2.2.2 The control efficiency of the VOC emission control system’s 

control device shall be determined by using EPA Methods 2, 2A, 

or 2D for measuring flow rates and EPA Method 25, 25A, or 25B 

for measuring total gaseous organic concentrations at the inlet and 

outlet of the control device. EPA Method 18 or ARB Method 422 

shall be used to determine the emissions of exempt compounds. 

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The control efficiency of the VOC emission control system’s 

control device shall be calculated by using the following equation: 

CECONTROL = [1 – ( VOCOUT / VOCIN )] x 100% 

Where: 

CECONTROL = Control Efficiency, in percent 

VOCIN = VOC content, in grams/liter, less exempt 

compounds and water, into the control device 

VOCOUT = VOC content, in grams/liter, less exempt 

compounds and water, out of the control device. 

6.2.2.3 For VOC emission control systems that consist of a single VOC 

emission collection device connected to a single VOC emission 

control device, the overall capture and control efficiency shall be 

calculated by using the following equation: 

CECAPTURE & CONTROL = [ CECAPTURE x CECONTROL ] / 100 % 

Where: 

CECAPTURE & CONTROL = Overall Capture and Control 

Efficiency, in percent 

CECAPTURE = Capture Efficiency of the collection device, 

in percent, as determined in Section 6.2.2.1 

CECONTROL = Control Efficiency of the control device, in 

percent, as determined in Section 6.2.2.2. 

6.2.3 Determination of VOC Emissions 

6.2.3.1 The emissions of VOCs, measured and calculated as carbon, 

shall be determined by using EPA Test Method 25, 25A, or 25B, 

as applicable. EPA Test Method 18 or ARB Method 422 shall be 

used to determine the emissions of exempt compounds. 

6.2.3.2 Total VOC emissions per day shall be determined for each 

source operation by using the following equation: 

1001 454

1 1

 Total E / %)/( x ⎥

⎦

⎤ ⎢

⎣

⎡ ⎟

⎠

⎞ ⎜

⎝

⎛ ⎟ + − ⎠⎞ ⎜

⎝

⎛ = ∑∑= =

VLVL CE

n

m

mm

k

i

ii

Where: 

ETotal = Total VOC emissions, in pounds per day 

Li = Liters per day used of the “i”th organic solvent 

that is uncontrolled 

Vi = Grams of VOC per liter of material of the “i”th 

organic solvent that is uncontrolled 

Lm = Liters per day used of the “m”th organic solvent 

that is controlled 

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Vm = Grams of VOC per liter of material of the “m”th 

organic solvent that is controlled 

CE = Overall capture and control efficiency of the 

control device, in percent, as determined in 

Section 6.2.2.3. 

6.2.4 Multiple Methods of Determination 

VOC emissions and overall capture and control efficiency determined to 

exceed any limits established by this rule through the use of any of the 

above-referenced test methods and equations shall constitute a violation of 

the rule. 

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